IDC expects tablet shipments to surpass PCs in the fourth quarter of 2013, while exceeding the total PC shipments annually by the end of 2015. Reuters

Worldwide shipments of tablet computers are projected to surpass total PC shipments (including desktops and portable PCs) in the fourth quarter of this year, according to a new research report from the International Data Corporation, or IDC.

The IDC report said that the worldwide market for smart devices, which includes PCs, tablets and smartphones, is expected to grow by 27.8 percent year-on-year in 2013, which is lower than the 30.3 percent growth the industry experienced in 2012. And, growth is expected to be driven mostly by tablet and smartphone shipments while the outlook for PC shipments has been lowered by 10 percent this year.

Although PC shipments are still expected to be greater than tablet shipments for the full year in 2013, IDC forecasts that tablet shipments will exceed total PC shipments on an annual basis by the end of 2015. And, smartphones will be the biggest contributors to worldwide shipments of all smart devices, exceeding 1.4 billion shipped units in 2015.

According to IDC, the market for smart devices worldwide is estimated to be $622.4 billion in 2013, of which $423.1 billion is projected to come from entry-level and mid-range smartphones and tablets with a price tag under $300-$350.

"At a time when the smartphone and tablet markets are showing early signs of saturation, the emergence of lower-priced devices will be a game-changer," Megha Saini, a research analyst at IDC, said in a statement. “Introducing new handsets and tablet devices at cheaper price points along with special initiatives like trade-in programs from Apple and BestBuy will accelerate the upgrade cycle and expand the total addressable market overnight.”

In addition, IDC also expects a new round of device cannibalization to occur with large-screen (5 inches or beyond) smartphones hurting the market share of smaller (7-8 inches) tablets.

"The device world has seen several iterations of cannibalization impacting different categories, with the last few years focused on tablets cannibalizing PC sales," Bob O'Donnell, program vice president of clients and displays at IDC, said in the statement. "Over the next 12-18 months, however, we believe the larger smartphones, commonly called 'phablets', will start to eat into the smaller-size tablet market, contributing to a slower growth rate for tablets."

According to a recent IDC report, smartphones with screen sizes of five inches to just under seven inches overtook shipments of the portable PC and tablet-device categories in the Asia-Pacific (excluding Japan) region during the three-month period from April to June.

IDC expects the smart device market worldwide to continue to grow, with overall shipments surpassing 2 billion units by the end of 2015 with a market value of $735.1 billion. By 2017, total PCs are expected to drop to 13 percent, while tablets and smartphones will contribute 16.5 percent and 70.5 percent respectively to the overall market.

And, the growing shift in demand from more expensive PCs to more reasonably-priced smartphones and tablets is expected to lower the average selling price for the collective market from $462 in 2012 to $323 in 2017, according to IDC.

IDC expects tablet shipments to surpass PCs in the fourth quarter of 2013, while exceeding the total PC shipments annually by the end of 2015. IDC